Area Forecast Discussion
Issued by NWS Sterling, VA

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KLWX 050130 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 930 PM EDT MON MAY 4 2015 .SYNOPSIS... HIGH PRESSURE IS CENTERED NEAR BERMUDA. A COLD FRONT OVER THE GREAT LAKES WILL PUSH SLOWLY SOUTH...STALLING ACROSS THE MID- ATLANTIC TUESDAY AND WEDNESDAY. HIGH PRESSURE IS EXPECTED TO RETURN TO THE REGION LATE IN THE WEEK WHILE LOW PRESSURE DEVELOPS OFF THE CAROLINA COAST. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... HIGH CLOUDS CONTINUE TO SPREAD IN AHEAD OF A COLD FRONT OVER THE GREAT LAKES. PREFRONTAL SHOWERS OVER ERN OH/WRN PA WILL DISSIPATE OVER THE POTOMAC HIGHLANDS TONIGHT WHERE SPRINKLES ARE POSSIBLE. MIN TEMPS LIMITED FROM SOUTH FLOW AND INCREASING CLOUDS...UPR 50S INLAND...WARMER AT ELEVATION DUE TO INVERSION...AND LOW 60S URBAN/NEARSHORE. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... A FNTL BNDRY XTNDS ACROSS QUEBEC..INTO MI AND THE MIDWEST. THIS WL BE SINKING INTO PA TNGT...WORKING SLOWLY TOWARD THE MASON-DIXON LN DURG THE DAY. POPS WL BE INCRSG DURG THE AFTN...ESPECIALLY ACROSS MD/ERN WV. BLV TEMPS WL STILL MAKE IT INTO THE LM80S OVR MUCH OF THE AREA. THE WIND FIELD ALOFT IS WEAK TUE. THIS WL PRECLUDE ANY CNVCTN THAT IS ABLE TO FORM FM DVLPG IN SVR STORMS. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... THERE IS MINOR DISAGREEMENT BETWEEN OPERATIONAL MODELS ON TIMING AND ORIENTATION OF THE WEAKENING COLD FRONT AS IT SLIPS SOUTH INTO THE AREA TUESDAY NIGHT AND WEDNESDAY. WHILE THIS COULD HAVE SOME INFLUENCE ON TEMPERATURES AND WHERE THE HIGHEST RAIN CHANCES ARE ORIENTED...SENSIBLE WX IMPACTS WILL BE RATHER MINIMAL DUE TO THE WEAK NATURE OF THE FRONT. BY TUESDAY EVENING...THE PARENT LOW IS NEARLY OUT OF THE PICTURE TO THE NE...WITH THE SFC FRONT STRETCHED BETWEEN HIGH PRESSURE CENTERS OVER THE GREAT LAKES AND NEAR BERMUDA. THERE SHOULD BE A DIURNAL DOWNTURN IN CONVECTION...ALTHOUGH THERE WILL REMAIN A CHANCE OF SHOWERS WITH THE FRONT NEAR THE NORTHERN PART OF THE CWA. CLOUDS AND ELEVATED DEW POINTS WILL KEEP LOWS IN THE MID 50S TO MID 60S. AS THE FRONT PROGRESSES SOUTHWARD WEDNESDAY...THE HIGHEST SHOWER CHANCES WILL BE OVER SOUTHERN AND WESTERN PORTIONS OF THE CWA. TERRAIN FORCING MAY PLAY A GREATER ROLE IN SHOWER DEVELOP UNDER THE WEAK FORCING REGIME. INSTBY REMAINS RATHER MEAGER...SO KEPT ONLY A SLIGHT CHANCE OF THUNDER. TEMPERATURES WILL BE A TOUCH COOLER...ESPECIALLY TOWARD NORTHERN MD. HIGHS RANGE FROM MID 70S TO LOWER 80S. SFC HIGH BUILDS TOWARD LONG ISLAND WEDNESDAY NIGHT...AS MID LEVEL RIDGE AXIS BUILDS TOWARD APPALACHIANS. NOT A PARTICULARLY DRYING INFLUENCE AS MOISTURE WILL REMAIN IN THE DECAYING FRONTAL ZONE. HOWEVER SHOWERS SHOULD DIMINISH WITH LOWS IN THE MID 50S TO NEAR 60. MAIN STORY DURING THE EXTENDED WILL BE CONTINUED ABV NORMAL TEMPS WITH LOW CHANCES OF PRECIP. THU LIKELY THE COOLEST DAY OF THE PERIOD...ALTHOUGH HIGH TEMPS WILL STILL BE U70S AS RETURN FLOW RECOMMENCES. HIGH TEMPS LIKELY L/M 80S DURING THE REMAINDER OF THE PERIOD...WHICH IS NEARLY 10 DEGREES ABV CLIMO NORMS. DEWPOINTS WILL ALSO RISE INTO THE L60S...WHILE NOT OPPRESSIVE...THE INCREASE IN LOW LEVEL MOISTURE WILL HELP KEEP NIGHTTIME LOWS IN M60S. DAILY PRECIP CHANCES FOR ANY ONE LOCATION HARD TO NAIL DOWN PRECISELY...AS FORCING IS RATHER NEBULOUS AND WILL BE PRIMARILY DIURNALLY DRIVEN. REGARDLESS...DEEP LAYER SHEAR RATHER WEAK...SO NOT EXPECTING ORGANIZED SVR WX. HOWEVER...INSTABILITY DOES INCREASE OVER THE WEEKEND SO THERE COULD BE A FEW ISOLATED STRONGER T-STORMS DURING THE AFTERNOON HOURS. && .AVIATION /01Z TUESDAY THROUGH SATURDAY/... VFR CONDS THROUGH TUESDAY MORNING. HIGH CIGS DEVELOP TONIGHT AND LOWER TO 5-10KFT RANGE TUE...ESPECIALLY BWI/MTN/MRB...ALTHO STILL STAYING AT VFR LVLS. RW/TRW LIKELY IN THE AFTN. CHANCES OF SHOWERS WILL LESSEN TUESDAY NIGHT BUT BE RENEWED WEDNESDAY. ISOLATED THUNDERSTORM POSSIBLE WEDNESDAY AFTERNOON. COVERAGE OF ANY AVIATION IMPACTS WOULD BE SCATTERED AND BRIEF. IF A MARINE INFLUENCE IS ESTABLISHED BEHIND A COLD FRONT...SUBVFR CIGS/VSBYS COULD BE POSSIBLE WEDNESDAY NIGHT. VFR CONDS THEN EXPECTED THURSDAY THROUGH THIS WEEKEND. && .MARINE... SLY CHANNELING OVERNIGHT WITH GUSTS AROUND 20 KT UP THE MAIN PART OF THE BAY INTO THE OVERNIGHT...CONTINUING FOR SRN MD WATERS REST OF THE NIGHT. COLD FRONT SLIPS THROUGH THE WATERS LATE TUESDAY NIGHT/ WEDNESDAY...SHIFTING WINDS FROM SW TO NE. COULD BE A HIGHER SURGE OF WINDS NEAR THE FRONT...BUT TIMING IS IN QUESTION AND GUSTS WILL BE MARGINAL IN TERMS OF SMALL CRAFT CONDITIONS. CHANCE OF SHOWERS AND ISOLATED STORMS LINGER INTO WEDNESDAY. LIGHT NE FLOW INTO WEDNESDAY NIGHT. NOT EXPECTING MARINE CONCERNS THROUGH REMAINDER OF THE PERIOD. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 2 AM EDT TUESDAY FOR ANZ530>533- 538>542. SMALL CRAFT ADVISORY UNTIL NOON EDT TUESDAY FOR ANZ534-543. SMALL CRAFT ADVISORY UNTIL 6 AM EDT TUESDAY FOR ANZ537. && $$ UPDATE...JACKSON PREVIOUS...WOODY!/ADS/MSE

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.